December 11, 2014

I updated the previous post Revit 2015 - Update Release 5 to include the specific download links for both Revit 2015 and Revit 2015 R2 users. There is a separate installer for each version of Revit 2015.

Also, for reference, I wanted to list the build numbers Revit reports after installing the noted update:

September 26, 2014

As mentioned previously the Revit Sundial Release preview has ended and Autodesk Revit 2015 R2 is now available for Autodesk Maintenance and Desktop Subscription customers. Click the following link for information on 39 Architectural, Structural, MEP, and multi-disciplinary enhancements made in R2:New in Revit 2015 R2

If you haven’t looked at the updates released for Revit (or Sundial), there could be some confusion between Revit 2015 R2 (Build: 20140905_0730), and Revit 2015 Update Release 2 (UR2) (Build: 20140323_1530).

If you look on the Revit download page, you should see that the latest 2015 update available is Update Release 4 (released 2014-09-21).

If you look on the Subscription Center, you will find Autodesk Revit 2015 R2 (released 2014-09-17).

R2 includes all of the updates included in Update Release 4 (and after installing will show Update Release 4 in the About Revit dialog), but also has added functionality available only to Autodesk Maintenance and Desktop Subscription customers.

Note: You cannot install both UR4 and R2. Additionally, if you inadvertently install UR4, and later realize that you want to load R2, you will need to uninstall Revit, reinstall, and then install R2.

Additional Note: As mentioned in the installation readme for UR4 (and R2) the update requires either the initial release of Autodesk Revit 2015 (build: 20140223_1515) or Autodesk Revit 2015 Update Release 3 (build: 20140606_1530). If UR1 or UR2 is installed, you will need to install UR3 prior to installing R2 or UR4.

We have recently found that the client-side portion of the hotfix is already included in UR3, but some of the DLLs were further changed with UR3.

This can lead to a situation where installing the client-side hotfix after UR3 will load an older version of three DLL files (DesktopMFC.dll, EssentialsDB.dll, RevitDB.dll), and the other changes in UR3 were not meant to work with those older DLLs. This is where we see the error above when launching Revit.

To clear the issue, restore the DLL files by renaming the 391388 appended version (e.g. DesktopMFC.391388.dll) back to the original file name or replace the DLL with the ones below: